Automatic draft appliance for furnaces



' NOV. 24,1931, HASENAUER 1,833,049

AUTOMATIC DRAFT APPLIANCE FOR FURNACES Filed- April 9, 1950 INVENTI'JR HTTDRNEY" LLE .3

Patented Nov. 24, 1931 UNITED STATES EDMUND J. HASENAUER, F

WHEELING, WEST VIRGINIA AUTOMATIC DRAFT APPLIANCE FOR FURNACES Application fiieaa rn 9,

This invention relates broadly to draft appliances for furnaces, and more particularly to an automatic draft control valve for furnaces of various types, including domestic Zil heating furnaces, stoves and the like.

The primary object of the invention is to provide a simple, inexpensive and efficient draft control valve or breather for furnaces, whereby air is automatically furnished to the I Furnace combustion chamber as needed and in the amounts required'to support proper combustion of the gases generated by the burning fuel.

A further object is to provide a device of the character mentioned by means of which are eliminated back-fires, or blow-outs, through the furnace door, resulting from ignition of accumulated unconsumed gases in the combustion chamber.

lVith these and other objects in view, the invention resides in the features of construction, arrangement of parts and combinations of elements which will hereinafter be fully described, reference being had to the accompanying drawings, in which- Figure 1 is a front perspective view of a furnace door equipped with my invention;

Figure 2 is a rear perspective view; and

Figure 3 is an enlarged section on line 33, Fig. 1.

Referring to said drawings, 1 designates a cast-iron fire door of the general concavoconvex type commonly employed on domestic heating furnaces, said door having an inwardly directed body-encircling rim 2 of flange-like form. Provided in an approximately central location in the body of said door is a draft passage 3 defined by integral inwardly extending throat-flanges 4. Mounted upon the inner, or convex, face of said door in seated relation to suitable inwardly direct-- ed studs 5 formed on the latter is a cover plate 7 which preferably rests also upon the terminal edges of said throat flanges 4, being secured to said door, as by suitably located attaching bolts 8. Said plate has therein an aperture or port 9 which registers With said throat or draft passage 3.

Mounted in pivoted depending relation to the inner face of said plate 7 is a damper-like 1930. Serial no. 442,794.

valve 10 by means of which is controlled the ingress of air to support combustion of fuel within the fuel chamber of the furnace, as also the outward passage through the threat- 3 of products of combustion. Said valve 10 is of check-valve type, consisting of a plate which in its gravity suspended position rests in closely seated relation to the plate 7 for closing the aperture 9 and, consequently, said i throat 3. To insure that said valve 10 shall remain normally a seated, as described, the plate 7 occupies a slightly downwardly and inwardly inclined position, as shown in Fig.3. i

As herein shown, the valve 10 suspended by strap-like hinge-members 11 from a horizontally disposed pin 12 mounted in, or supported by, a plate-like hinge member 13 attached to the plate 7, as by means of an attaching screwor bolt 14-.

YVhile the valve 10 positively obstructs the outward passage through the port 9 and throat 3 of products of combustion, it is free to swing inwardly, induced by suction created 7 within the combustion chamber, thus to a mit fresh air to said chamber as the same may be required to facilitate combustion of the fuel-and the generated gases.

In practice, the valve ordinarily is actuated at frequent and substantially uniform. inter- .vals to swing inwardly from its normally seated position, shown in full lines in Fig. 3, to or toward the dotted line position shown in said figure, such movements alternating with gravity-actuated return movements to its said normal position. Thus, said valve'is almost continuously in motion, the'inwardly swinging movements being induced by suction created by the formation within the fuel chamber of the partial vacuum resulting from the siphoning action of the flue which leads from the chamber.

As is well understood, it frequently occurs that, due to poor or inactive combustion of fuel within the furnace chamber, gases arising from the smouldering fuel accumulate in such amounts orquantities that, when ignition thereof takes place, more or less violent explosions result, such ordinarily being evidenced by back-flashes, commonly termed back-fires or blow-outs, wherein flashes of flame, smoke and soot are expelled through the usual forms of hand-controlled damper openings provided in furnaoe doors. Not only are such objectionable results practically eliminated by the automatic operation of the valve as herein described, but, in the event that such slight explosion should occur, the valve is instantly actuated to seat, thereby positively preventing the outward expulsion of products of combustion through the door.

What is claimed is- 1. In an automatic draft control device for furnaces, the combination with a door for the combustion chamber of the furnace, said door having a throat-like draft passage leading therethrough, of a pivotally suspended valve normally maintained by gravity acting thereon in vertically pendent position wherein it occupies seated closing relation to the inner end of said passage and preventing backfiashing through said passage, said valve being free to swing inwardly and being adapted for actuation to inwardly swung passageopening position under air-siphoning force exerted thereon.

2. In an automatic draft control device for furnaces, the combination with a door for the combustion chamber of the furnace, said door having a throat-like draft passage leading therethrough, of a plate fixed in a (lOW11-' ivardly and. inwardly inclined position on the inner face of said door, said plate having therein a port located in register with the inner end of said passage, and a valve pivotally mounted on the inner face of said plate and normally maintained by gravity in seated closing relation to said port, said valve being adapted to seat for preventing backllashing through said passage and being freely movable in inward direction under airsiphoning force exerted Within said chamber.

3. In an automatic draft control device for furnaces, a door for the combustion chamber of the furnace, said door having concavoconvex form and having therein a throat-like draft passage defined by inwardly directed iang s, a plate fixed upon the inner side of said door in seated relation to the edges of said throat flanges and having therein an opening which registers with said passage, and a free-swinging valve pivotally mounted on the inner face of said plate and normally held by gravity in seated. closing relation to said opening, said valve serving to bafile back-flashing through said passage and being adapted for actuation to inwardly swung passagebpening position under air-siphoning force exerted Within said chamber.

In testimony whereof, I aliix my signature.

EDMUND J. HASENAUER, 

